Sometimes slight movement due to vibration or due to creep due to thermal cycling (warm/cold) moves the pins and due to surface contamination, a poor connection is formed.
Removing the chip and replacing it helps to clean the surfaces of both the chip pins and the surfaces of the socket.
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Muttley Black wrote: ↑Sat Jun 13, 2020 7:47 am
Well done my friend!
Thanks!!!
1024MAK wrote: ↑Sat Jun 13, 2020 10:12 am
Good that it’s working now
Sometimes slight movement due to vibration or due to creep due to thermal cycling (warm/cold) moves the pins and due to surface contamination, a poor connection is formed.
Removing the chip and replacing it helps to clean the surfaces of both the chip pins and the surfaces of the socket.
Mark
Thanks.. Some times we have to expand the limits of the logic and provoque the good luck to happen..
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
avrovulcan wrote: ↑Sun Jun 14, 2020 7:39 pm
Glad you've got your 80 working. This thread has give me a bit of a nudge and reminded me that I have my own to finish repairing.
Lets make that happen!!
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
Will do. I don't think I had much else to do. Replace the broken off ceramic resonator with a crystal oscillator and replace the voltage regulator. Hopefully the EPROM is still viable, I've kept it out of direct UV light, but it depends on how the previous owner stored it. If needs be I'll erase and reflash it. If that doesn't work I'll replace it. I'm sure I'll have something I can use from all the EPROM's I've bought over the years.
avrovulcan wrote: ↑Tue Jun 16, 2020 8:57 pm
Will do. I don't think I had much else to do. Replace the broken off ceramic resonator with a crystal oscillator and replace the voltage regulator. Hopefully the EPROM is still viable, I've kept it out of direct UV light, but it depends on how the previous owner stored it. If needs be I'll erase and reflash it. If that doesn't work I'll replace it. I'm sure I'll have something I can use from all the EPROM's I've bought over the years.
Regards
Andy
I have a CZ1000 with resonator issues but can't find any replacement here ... how do you replace it with a crystal? I don't get any at 6.5MHz either ...
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
Depending on where you live you could use Mouser or Digikey.
The the legs of the crystal oscillator go to the two outer holes where the resonator used to be, the middle hole isnt used. In any case the middle hole is electrically tied to one of the mounting holes anyway. It won't matter which way round you mount the crystal.
See the picture on Grant Searle's web pages for more information. The picture of the crystal oscillator is about half way down his ZX80 page.
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